Passive shock absorber for treadmill

ABSTRACT

A passive shock absorber for a treadmill includes a tall damping member and a short stopping member for supporting the tall damping member. Both the tall damping and the short stopping members have a top, a bottom and a spring stiffness, respectively. The tall damping and the short stopping member are combined together and are mounted in the treadmill. The passive shock absorbers are adapted to mount under a flat stationary member on which a person walks, runs or jogs. The top of the tall damping member abuts the flat stationary member. Consequently, the tall damping member can absorb impacts on the person&#39;s feet and the short stopping member will stop a compression of the tall damping member as the tall damping member is suddenly deformed and compressed.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a passive shock absorber for atreadmill, and more particularly to a simple passive shock absorber fora treadmill that will efficiently cushion impacts of and absorb impactforces on a runner's foot.

[0003] 2. Description of Related Art

[0004] Treadmills are pieces of exercise equipment used by people towalk, run or jog in place. However, walking, running or jogging on thetreadmill will impart impacts that will incur a possibility of a sportinjury to the feet, ankles and knees to a person who is exercising onthe treadmill. The impacts are caused by the force of the person's footstriking a flat stationary member, also called a deck, of the treadmill.The impacts on the person's foot must be reduced as the person runs,jogs or walks on the treadmill otherwise, the unattenuated impacts willcause the person who runs or jogs on the treadmill to feel uncomfortableand probably injure the person's feet, ankles or knees.

[0005] Therefore, to efficiently absorb or dissipate the impacts on theperson's foot while running on the treadmill, passive shock absorbersare mounted in the treadmill to diminish effects of the impacts. Aconventional passive shock absorber for a treadmill is a block of adamping material. Consequently, the conventional passive shock absorberonly has a single spring stiffness and damping characteristic. However,different people using the treadmill will be of different weights andhave different exercise preferences that cause different forces tostrike the flat stationary member of the treadmill. The different forceswill cause the impacts on the person's feet to have differentmagnitudes. The single spring stiffness and damping characteristics ofthe conventional passive shock absorber cannot dissipate the entirerange of impacts caused by different people. In a worst condition, theunattenuated impacts will make the exerciser feel uncomfortable and eveninjure the person, as previously described.

[0006] To overcome the shortcomings, the present invention provides apassive shock absorber for a treadmill to mitigate or obviate theaforementioned problems.

SUMMARY OF THE INVENTION

[0007] The main objective of the invention is to provide a simplepassive shock absorber for a treadmill to dissipate impacts caused by aperson striking a flat stationary member of the treadmill as the personwalks, runs or jogs on the treadmill.

[0008] The passive shock absorber is mounted in the treadmill below theflat stationary member and comprises a tall damping member and a shortstopping member. Each of the tall damping and the short stopping membershas a separate top, bottom, spring stiffness, shape and dampingcharacteristic. The tall damping member is taller than the shortstopping member. When a person runs on the treadmill, energies of theimpacts on the person's foot will be absorbed or dissipated by the talldamping member of the passive shock absorber.

[0009] If the impact forces are so large that the tall damping membercannot absorb or dissipate all the energy in the impact, the talldamping member will be deformed and compressed whereafter the shortstopping member will limit the compression of the tall damping member toprevent that from being completely deformed. Furthermore the shortstopping member can also be made of viscoelastic material and willfurther absorb and attenuate the impacts when the tall damping member isentirely compressed. Under such a condition, the tall damping and theshort stopping members cooperate with each other to absorb or dissipatethe impacts on the person's feet.

[0010] Other objectives, advantages and novel features of the inventionwill become more apparent from the following detailed description whentaken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 is a perspective view of a treadmill with multiple passiveshock absorbers in accordance with the present invention;

[0012]FIG. 2 is an enlarged cross sectional side plan view of a passiveshock absorber in FIG. 1 mounted in a treadmill;

[0013]FIG. 3 is a perspective view of the passive shock absorber in FIG.2;

[0014]FIG. 4 is a perspective view of a second embodiment of a passiveshock absorber in accordance with the present invention;

[0015]FIG. 5 is a perspective view of an alternative configuration ofthe passive shock absorber in FIG. 3; and

[0016]FIG. 6 is a perspective view of an alternate configuration of thesecond embodiment of the passive shock absorber in FIG. 4.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

[0017] With reference to FIG. 1, a treadmill is conventional comprises atread frame assembly (10) and a front support (20). The tread frameassembly (10) comprises a tread frame (11) and a moving tread assembly(12). The tread frame (11) has a top (not numbered), a bottom (notnumbered), a front (not numbered), a rear (not numbered) and twoopposite sides (not numbered). Multiple transverse rods (111) aremounted between the sides of the tread frame (11) for passive shockabsorbers (30) being mounted in the treadmill. For illustrationpurposes, only one transverse rod (111) is shown in FIG. 1. Eachtransverse rod (111) has a top (not numbered) and two ends (notnumbered) respectively attached to the opposite sides of the tread frame(11).

[0018] The moving tread assembly (12) is mounted in the tread frame (11)and comprises a flat stationary member (121), a moving tread (122) androllers (not shown). The rollers are mounted in the tread frame (11)respectively at the front 11 and the rear. The flat stationary member(121) is mounted on the top of the tread frame (11) between the rollersin the tread frame (11) and has a top (not numbered) and a bottom (notnumbered). The moving tread (122) is a wide endless belt and is mountedaround the rollers and the flat stationary member (121) to form a flatmoving surface (not numbered) on the top of the flat stationary member(121). A person can walk, run or jog in place on the flat moving surfaceof the moving tread (122) because the moving tread (122) rotates aroundthe rollers.

[0019] Multiple passive shock absorbers (30) in accordance with thepresent invention are mounted on the top of each transverse rod (111)under the bottom of the flat stationary member (121). However, positionsof the passive shock absorbers (30) in the tread frame (11) are notlimited to the disclosed embodiment. Such a statement means the passiveshock absorbers (30) can be mounted at the sides of the tread frame (11)or other positions below the bottom of the flat stationary member (121).

[0020] With reference to FIGS. 2 and 3, each passive shock absorber (30)comprises a tall damping member (31) and a short stopping member (32).Both the tall damping and the short stopping members (31, 32)respectively have both elasticity, regarded as spring stiffness, and adamping characteristic, regarded as a damping coefficient. The shortstopping member (32) is cylindrical and has an axial center (notnumbered), a top (not numbered), a bottom (not numbered), an outerperiphery (not numbered) and a height. A mounting hole (33) is definedaxially from the top to the bottom of the short stopping member (32).The tall damping member (31) is cylindrical and has a top (notnumbered), a bottom (not numbered), an axial through hole (not numbered)and a height. The axial through hole of the tall damping member (31) isdefined through the top of which. The outer periphery of the shortstopping member (32) is received in the axial through hole of the talldamping member (31). The bottoms of both of the tall damping and theshort stopping members (31, 32) are flush with each other and aremounted against the top of the transverse rod (111) in the tread frame(11). The passive shock absorber (30) is securely mounted in thetreadmill between the transverse rod (111) and the flat stationarymember (121) by a fastener (21). The fastener (21) has an enlarged end(not numbered) and a threaded end (not numbered). The threaded endpasses through the flat stationary member (121) and the mounting hole(33) and screws into the transverse rod (111). The height of the talldamping member (31) is taller than the height of the short stoppingmember (32). Consequently, only the top of the tall damping member (31)initially abuts the bottom of the flat stationary member (122).

[0021] The tall damping member (31) is made of viscoelastic material.The short stopping member (32) is made of a hard substance orviscoelastic material. Examples of viscoelastic materials and devicesinclude rubber, plastic, cork, metal springs and pneumatic springs.Examples of the hard substance include hard rubber (an elastomer),plastic with a high rigidity or the like. The spring stiffness of thetall damping member (31) is larger than the spring stiffness of theshort stopping member (32), which means the tall damping member (31) issofter than the short stopping member (32).

[0022] Consequently, the impacts on a person's foot will be transmittedto the tall damping members (31) when the person is walking, running orjogging on the flat moving surface of the tread frame (11). Energy fromthe impact will be absorbed or dissipated by the tall damping member(31). If the impacts are too large, the tall damping member (31) will bedeformed and compressed. The hard short stopping member (32), supportingthe tall damping member (31), will limit a compression of the talldamping member (31) to prevent that from being completely deformed.Furthermore, if the short stopping member (32) is made of viscoelasticmaterial, the tops of both of the tall damping and the short stoppingmembers (31, 32) will abut the bottom of the flat stationary member(121) as the tall damping member (31) is entirely deformed. Both thetall damping and the short stopping members (31, 32) cooperate with eachother to absorb or dissipate efficiently the large impacts on theperson's feet. Therefore, the impacts on the person's feet aresignificantly absorbed and only a few greatly attenuated impacts will betransmitted in a diminished form to the person's foot. Thus, the passiveshock absorber (30) can allow the person walking, running or jogging onthe treadmill to feel comfortable and not be injured by the impacts.

[0023] With reference to FIG. 4, a second embodiment of a passive shockabsorber (40) in accordance with the present invention has the sameinventive features as the previously described embodiment except for thearrangement of the tall damping and the short stopping members (31, 32).The second embodiment of passive shock absorber (40) in accordance withthe present invention comprises a tall damping member (41) and a shortstopping member (43). The tall damping member (41) is cylindrical andhas an axial center, a top (not numbered), a bottom (not numbered), anouter periphery (not numbered) and a height. A mounting hole (42) isdefined axially from the top to the bottom of the tall damping member(41). The short stopping member (43) is cylindrical and has a top (notnumbered), a bottom (not numbered), an axial through hole (not numbered)and a height. The axial through hole of the short stopping member (43)is defined through the top of which. The outer periphery of the talldamping member (41) is received in the axial through hole of the shortstopping member (43), with the bottoms of the members (41,43) beingflush with each other. The tall damping and the short stopping members(41, 43) are made of previously described materials. The springstiffness of the tall damping member (41) is larger than the springstiffness of the short stopping member (43), which means the talldamping member (41) is softer than the short stopping member (43).

[0024] Therefore, the structure and characteristics of the secondembodiment of the passive shock absorber (40) are equivalent to thestructure and features of the previously described passive shockabsorber (30), and the mounting and operation of the second embodimentof the passive shock absorber (40) is the same as the previouslydescribed passive shock absorber (30). Therefore, further description isomitted.

[0025] With reference to FIGS. 5 and 6, the passive shock absorbers inaccordance with the present invention can also be implemented to havethe essential characteristics of the first and second embodiments of thepassive shock absorbers (30, 40) in the foregoing description whilechanging the shapes of the tall damping and the short stopping member(31, 32, 41, 43).

[0026] With reference to FIG. 5, a third embodiment of a passive shockabsorber (50) comprises a short stopping member (51) and two talldamping members (53). The short stopping member (51) is a rectangularparallelepiped with two opposite long sides (not numbered) instead ofthe cylindrical first embodiment of the short stopping member (32). Twotall damping member (53) are also rectangular parallelepiped instead ofbeing cylindrical as is the first embodiment of the tall damping member(31). The tall damping members (53) are attached respectively to thelong sides of the short stopping member (51). A mounting hole (52) isformed through the short stopping member (51) that is used to attach thepassive shock absorber (50) in a manner similar to the previousembodiments of the passive shock absorber.

[0027] With reference to FIG. 6, a fourth embodiment of a passive shockabsorber (60) is a complementary version of the third embodiment andcomprises a tall damping member (61) and two short stopping members(63). The tall damping member (61) is rectangular parallelepiped withtwo opposite long sides (not numbered) instead of the cylindrical secondembodiment of the tall damping member (41). Two short stopping members(63) are also rectangular parallelepiped instead of being cylindrical asis the second embodiment of the short stopping member (43). The shortstopping members (63) are attached to the long sides of the tall dampingmember (61). A mounting hole (62) formed through the tall damping member(61) that is used to attach the passive shock absorber (60) in a mannersimilar to the previous embodiments of the passive shock absorber.

[0028] The passive shock absorber is simple which results in the passiveshock absorber being cheap and easy to manufacture. Because the talldamping and the short stopping members have different spring stiffnessesand damping characteristics, the passive shock absorber will absorb awide range of impacts and minimize the effect of the impacts on theperson's feet. Thereafter, the passive shock absorbers will allow anexerciser to feel comfortable when walking, running or jogging on thetreadmill and prevent the person from being injured by the impacts.

[0029] Even though numerous characteristics and advantages of thepresent invention have been set forth in the foregoing description,together with details of the structure and function of the invention,the disclosure is illustrative only, and changes may be made in detail,especially in matters of shape, size, and arrangement of parts withinthe principles of the invention to the full extent indicated by thebroad general meaning of the terms in which the appended claims areexpressed.

What is claimed is:
 1. A passive shock absorber for a treadmill having atread frame and a moving tread assembly, the moving tread assemblyhaving a flat stationary member with a bottom, and the passive shockabsorber adapted to be mounted between the thread frame and the bottomof the flat stationary member and comprising: at least one tall dampingmember having a spring stiffness, a damping characteristic, a top, abottom and a height and the at least one tall damping member being fordissipating impact energy on a person's feet; and at least one shortstopping member combined with the at least one tall damping membertogether and the at least one short stopping member having a springstiffness, a damping characteristic, a top, a bottom and a height andthe at least one short member being for stopping a compression of the atleast one tall damping member; wherein the spring stiffness of the atleast one tall damping member is larger than the spring stiffness of theat least one short stopping member and the height of the at least onetall damping member is greater than the height of the at least one shortstopping member.
 2. The passive shock absorber as claimed in claim 1,wherein the at least one short stopping member is made of viscoelasticmaterial for dissipating impact energy on the person's feet as the topof the at least one short stopping member abuts the bottom of the flatstationary member.
 3. The passive shock absorber as claimed in claim 1,wherein the passive shock absorber has one tall damping member having acylindrical shape, an axial center and an outer periphery; and one shortstopping member attached to the outer periphery of the tall dampingmember and having a cylindrical shape and an axial through hole, theouter periphery of the tall damping member being received in the axialthrough hole of the short stopping member.
 4. The passive shock absorberas claimed in claim 1, wherein the passive shock absorber has one talldamping member having a rectangular parallelepiped shape with twoopposite long sides; and two short stopping members respectivelyattached to the long sides of the tall damping member, each shortstopping member having a rectangular parallelepiped shape and attachedto a corresponding one of the long sides of the tall damping member. 5.The passive shock absorber as claimed in claim 1, wherein the passiveshock absorber has one short stopping member having a cylindrical shape,an axial center and an outer periphery; and one tall damping memberattached to the outer periphery of the short stopping member and havinga cylindrical shape and an axial through hole, the outer periphery ofthe short stopping member being received in the axial through hole ofthe tall damping member.
 6. The passive shock absorber as claimed inclaim 1, wherein the passive shock absorber has one short stoppingmember having a rectangular parallelepiped shape with two opposite longsides; and two tall damping members respectively attached to the longsides of the short stopping member, each tall damping member having arectangular parallelepiped shape and attached to a corresponding one ofthe long sides of the short stopping member.
 7. The passive shockabsorber as claimed in claim 3, wherein a mounting hole is axiallydefined through the top to the bottom of the tall damping member.
 8. Thepassive shock absorber as claimed in claim 4, wherein a mounting hole isdefined through the top to the bottom of the tall damping member.
 9. Thepassive shock absorber as claimed in claim 5, wherein a mounting hole isaxially defined through the top to the bottom of the short stoppingmember.
 10. The passive shock absorber as claimed in claim 6, wherein amounting hole is defined through the top to the bottom of the shortstopping member.